RestFul Resource

images_controller.rb

class ImagesController < ApplicationController
  before_action :load_parent_resource

  include RestfulResources
  restful_resources resource_name: :image

  private

  def load_resources
    @images = resource_scope.all.group_by(&:kind)
  end

  def load_parent_resource
    @product ||= Product.find(params[:product_id])
  end

  def build_resource
    @image ||= Image::ImageBuilder.new
    @image.attributes = resource_params
  end

  def resource_params
    resource_params = params.fetch(:image_image_builder, {})
    resource_params.permit!.merge(viewable_type: 'Product::Variant')
  end

  def resource_scope
    @product.variant_images
  end
end

restful_resources.rb

module RestfulResources

  extend ActiveSupport::Concern

  included do
    before_action :load_resource, only: %i(show edit update destroy)
  end

  module ClassMethods
    def restful_resources(options = {})
      cattr_accessor :resource_name
      self.resource_name = options[:resource_name]
    end
  end

  def index
    load_resources
  end

  def new
    build_resource
  end

  def create
    build_resource
    save_resource or render 'new'
  end

  def update
    build_resource
    save_resource or render 'edit'
  end

  def destroy
    destroy_resource
  end

  private
  # Use callbacks to share common setup or constraints between actions.
  def load_resources
    resources = instance_variable_get("@#{self.class.resource_name.to_s.pluralize}")
    resources ||= resource_scope.page(params[:page])
    instance_variable_set("@#{self.class.resource_name.to_s.pluralize}", resources)
  end

  def load_resource
    resource = instance_variable_get("@#{self.class.resource_name}")
    resource ||= resource_scope.find(params[:id])
    instance_variable_set("@#{self.class.resource_name}", resource)
  end

  def build_resource
    resource = instance_variable_get("@#{self.class.resource_name}")
    resource ||= resource_scope.new
    resource.attributes = resource_params
    instance_variable_set("@#{self.class.resource_name}", resource)
  end

  def save_resource
    resource = instance_variable_get("@#{self.class.resource_name}")
    resource.save
  end

  def destroy_resource
    resource = instance_variable_get("@#{self.class.resource_name}")
    resource.destroy
  end

  def resource_scope
    self.class.resource_name.to_s.classify.constantize
  end

  # Never trust parameters from the scary internet, only allow the white list through.
  def resource_params
    resource_params = params.fetch(self.class.resource_name.to_sym, {})
    resource_params.permit!
  end
end

spaces_controller.rb

class SpacesController < ApplicationController
  include RestfulResources
  restful_resources resource_name: :space
end